Document detecting device and document detecting method

ABSTRACT

Certain embodiments provide a document detecting device, including: a plate having an upper surface on which a document is placed; an imaging device that includes the upper surface in a photographing visual field range; and a controller that detects any one or more of a position, an angle, and a size of the document on the upper surface according to an image by the imaging device and fixed-size information of the document stored in advance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 14/728,006filed on Jun. 2, 2015, the entire contents of which are incorporatedherein by reference.

FIELD

Embodiments described herein relate generally to a document detectingdevice and a document detecting method.

BACKGROUND

A copying machine includes a reading device of an image.

According to a size detecting device provided in the copying machine inadvance, or an input of a user, the reading device acquires documentsize information. The reading device reads an image of a document.

In the related art, the reading device includes a surface area within aglass plate as a reading target. The surface area is designated by amovable range of a reading unit such as a carriage.

In the reading device, the premise is that the position and the size ofthe document match the surface area.

However, the position of the document may not match the designatedposition. Otherwise, a user may input incorrect document sizeinformation.

The reading device cannot accurately perform reading.

The read image deviates from a desired image. In a document having anunfixed size, the reading for an accurate document size cannot beperformed.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a document detecting device according toa first embodiment;

FIG. 2 is a configuration diagram of an image reading device;

FIG. 3 is a block diagram of a control system;

FIG. 4 is a flowchart for describing a detecting process;

FIG. 5 is a top view of the document detecting device according to thefirst embodiment;

FIG. 6 is a diagram illustrating an example of an acquired image;

FIG. 7 is a flowchart for describing an example of an inclinationcorrecting process;

FIG. 8 is a flowchart for describing a detecting process of a documentdetecting device according to a modification example;

FIG. 9A is a diagram illustrating a display example of a display;

FIG. 9B is a diagram illustrating another display example of thedisplay;

FIG. 10A is a top view of a reading device including a documentdetecting device according to a second embodiment; and

FIG. 10B is a diagram illustrating a vertical cross-sectional structure.

DETAILED DESCRIPTION

Certain embodiments provide a document detecting device, including: aplate having an upper surface on which a document is placed; an imagingdevice that includes the upper surface in a photographing visual fieldrange; and a controller that detects any one or more of a position, anangle, and a size of the document on the upper surface according to animage by the imaging device and fixed-size information of the documentstored in advance.

Hereinafter, a document detecting device and a document detecting methodwill be described in detail with reference to the attached drawings. Thesame reference sign will be given to the same portion in each drawing,and the redundant description will be omitted.

First Embodiment

FIG. 1 is a perspective view of a document detecting device according toa first embodiment.

A document detecting device 10 includes a glass plate 11, a camera 12,and a controller 13. A reference sign G indicates a document.

The glass plate 11 includes a glass surface 14 (upper surface) on whichthe document is placed.

The camera 12 is an imaging device that includes the glass surface 14 ina photographing visual field range.

The controller 13 detects a position, an angle, and a size of thedocument on the glass surface 14 according to an image photographed bythe camera 12 and fixed-size information of the document which is storedin advance.

FIG. 2 is a configuration diagram of a scanner 17 including the documentdetecting device 10. FIG. 2 illustrates a copying machine 100.

The scanner 17 is a reading device that reads a document surface of thedocument.

The glass plate 11 is a platen of the scanner 17. The glass plate 11 ismainly formed of a transparent material. The glass plate 11 transmitslight.

The scanner 17 includes a light source 18, mirrors 19, 20, and 21, alens 22, and a 4-line CCD 23.

The scanner 17 further includes carriages 28 and 29 below the glassplate 11. The carriage 28 fixes the mirror 19. The carriage 29 fixes themirrors 20 and 21.

The carriages 28 and 29 move in parallel with the glass plate 11. Thecarriages 28 and 29 receive power for moving from a belt driven by amotor.

The 4-line CCD 23 outputs electric charge information for each color toa page memory 112 of the copying machine 100.

The document detecting device 10 includes the camera 12 in FIG. 1 on arear surface 16 of a cover 15.

In FIG. 1, the cover 15 has one end on an upper front side, and theother end on a lower depth side. The two ends are laterally parallelwith each other.

The cover 15 has a hinge 24 at the other end.

The cover 15 is opened or closed with respect to the glass plate 11 bythe hinge 24.

The document detecting device 10 includes the camera 12 at the center ofthe one end opposite to the other end in the rear surface 16.

A photographing direction of the camera 12 is a direction facing theglass surface 14.

The direction indicates a direction in which the camera 12 can recognizethe entirety of the glass surface 14 when the cover 15 is opened at apredetermined angle or larger.

The cover 15 covers the glass surface 14 with the rear surface 16. Therear surface 16 is a protective surface of the glass surface 14.Otherwise, the cover 15 blocks natural light.

The cover 15 is attached to an automatic document feeder (ADF) 25.Otherwise, the ADF 25 may also serve as the cover 15 by using the bottomsurface of the ADF 25.

The ADF 25 has the cover 15 at the rear sides of a slope 32 and a mainbody 33.

The ADF 25 transports a bundle of documents one by one to a readingposition. The reading position exists right above a slit 30.

The ADF 25 includes a tray 26, a plurality of rollers 27 having axesthat are parallel with each other, a drum 31, the slope 32, and the mainbody 33.

The ADF 25 forms the slit 30 between a part of the main body 33, theglass plate 11, and the slope 32.

The document detecting device 10 is electrically connected to anoperation panel 101 of the copying machine 100 and a controller 102 onthe side of the copying machine 100.

The document detecting device 10 of FIG. 1 includes an opening andclosing detector 35.

The opening and closing detector 35 detects an open state and a closedstate of the cover 15.

The open state indicates a state in which the cover 15 is openedrelative to the glass surface 14.

The closed state indicates a state in which the cover 15 is closedrelative to the glass surface 14.

For example, a contact switch is used for the opening and closingdetector 35.

The document detecting device 10 may include an angle detector 36 and adisplay 37.

The angle detector 36 detects an opening angle formed between the glasssurface 14 and the rear surface 16 of the cover 15.

The angle detector 36 is configured of, for example, a volume resistor34 and a voltage generation detector 44. One end of the volume resistor34 is fixed to the rear surface 16 of the cover 15. The other end of thevolume resistor 34 is fixed to the glass surface 14.

The voltage generation detector 44 causes a voltage to be generated. Thevoltage generation detector 44 detects the change of the volume resistor34 according to the opening angle of the cover 15.

The display 37 may be provided on the operation panel 101 of the copyingmachine 100. Otherwise, the display 37 may be used in common with awindow of the operation panel 101.

FIG. 3 is a block diagram of a control system 50 of the documentdetecting device 10 according to the first embodiment. Reference signsdescribed above represent the same components.

The controller 13 is connected to the opening and closing detector 35,the angle detector 36, the display 37, and a storage unit 38 via a bus39.

The controller 13 calculates the position, the angle, the size of thedocument according to the detection of the open state by the opening andclosing detector 35.

The controller 13 calculates the position, the angle, and the size byusing a memory table or a calculating expression.

The controller 13 causes the display 37 to display a state in which theposition, the angle, and the size can be recognized based on an outputof the angle detector 36 and the angular range information stored inadvance in the storage unit 38.

The document detecting device 10 may be provided with a determinationunit 45. The determination unit 45 determines whether the opening angleis within an angular range. The determination unit 45 sends thedetermination result to the controller 13.

The controller 13 is connected to the operation panel 101 via a bus 40that is separately provided in the copying machine 100.

The controller 13 allows the operation panel 101 to receive arecognition operation of the position, the angle, or the size based onthe output of the angle detector 36 and the angular range information ofthe storage unit 38.

The controller 13 inputs signals representing buttons and keys from theoperation panel 101.

The controller 13 may cause the display 37 to display the completion ofthe detection of the position, the angle, and the size.

The functions of the controller 13 and the determination unit 45 areexecuted by a CPU 41, a ROM 42, and a RAM 43.

The CPU 41 is provided on a control substrate in the document detectingdevice 10.

The ROM 42 stores an application program for calculating the position,the angle, and the size. The ROM 42 may store values necessary for thecalculation, a memory table or a calculating expression.

The RAM 43 provides a storage area for work to the CPU 41.

A storage medium 47 is used for the storage unit 38. The storage medium47 is hard disk drive (HDD) or solid state drive (SSD). The storage unit38 stores the angular range information.

Further, the storage unit 38 stores an image of the glass surface 14 onwhich the document is not placed. The scanner 17 photographs the glasssurface 14 without a document in advance.

The storage unit 38 stores the fixed-size information of the document.The fixed-size information includes dimensions of a short side and along side of a sheet.

The fixed-size information is, for example, A4, B4, and A3 ofinternational organization for standardization (ISO) 216.

The fixed-size information is, for example, letter, legal, and ledger.

In addition, the storage unit 38 stores an upper limit angle and a lowerlimit angle of the angular range.

The upper limit angle is a wide angle at which a part of the glasssurface 14 is out of the photographing visual field range.

The lower limit angle is a narrow angle at which a part of the glasssurface 14 is out of the photographing visual field range.

In the angular range, the entire region of the glass surface 14 iscovered by the photographing visual field range of the camera 12.

The angular range is based on an angle of view for photographing that animage sensor of the camera 12 has. The angular range is based on theattaching position of the camera 12 to the cover 15 and the planar sizeof the cover 15.

The angular range is determined in advance by a simulation and filedtest.

In addition, in FIG. 2, the copying machine 100 includes an imageprocessing unit 103, a printing unit 104, a fixing unit 109, a paperfeeding unit 110, a paper discharging unit 111, and a page memory 112.

The image processing unit 103 performs color conversion on image data ofthree colors of R, G, and B to four printing colors of Y, M, C, and K byusing the page memory 112.

The printing unit 104 includes an image forming unit 105 for yellow, animage forming unit 106 for magenta, an image forming unit 107 for cyan,and an image forming unit 108 for black.

The image forming unit 105 for yellow includes a photosensitive drum, acharger that charges the photosensitive drum, and an exposure devicethat irradiates the photosensitive drum with laser light, which are notillustrated.

Further, the image forming unit 105 includes a developing device thatdevelops an electrostatic latent image and a transfer device thattransfers a toner image on a sheet.

The printing unit 104 is supplied with a sheet from the paper feedingunit 110.

The image forming unit 106 for magenta, the image forming unit 107 forcyan, and the image forming unit 108 for black have a configurationsubstantially the same as that of the image forming unit 105 for yellow.

The fixing unit 109 fixes a toner image on a sheet by a heat roller anda press roller.

The copying machine 100 outputs a sheet from the fixing unit 109 via thepaper discharging unit 111.

In addition, the document detecting method according to the embodimentis photographing of an image by the camera 12 in a state where a partbetween the glass surface 14 and the rear surface 16 of the cover 15 isopened.

The method is detecting of any one or more of the position, the angle,and the size of the document on the glass surface 14 based on the imageand the fixed-size information of the document.

In the photographing of an image by the camera 12, a method is detectingof the open state or the closed state of the cover 15 by the opening andclosing detector 35.

In the photographing of an image, a method is determining of thedetermination unit 45 on whether the opening angle by the angle detector36 is within an angular range by the controller 13.

The operation of the document detecting device 10 will be described.

FIG. 4 is a flowchart for describing a detecting process of the documentdetecting device 10.

FIG. 5 is a top view of the document detecting device 10. FIG. 5illustrates an example in which the cover 15 is removed. Reference signsdescribed above represent the same components.

Before a detecting process starts, a user places a document at anarbitrary position on the glass surface 14.

The position of the cover 15 is set as a fully open position. The fullyopen position indicates a state in which the cover 15 is erected oralmost erected on the glass surface 14.

In Act A1 of FIG. 4, the document detecting device 10 detects theopening angle of the cover 15 by the opening and closing detector 35.

In Act A2, the document detecting device 10 continuously monitorswhether or not the opening angle is within the angular range (route N ofACT A2).

In Act A2, the document detecting device 10 compares the opening angleby the angle detector 36 with the angular range information.

In Act A2, the document detecting device 10 detects that the cover 15has a predetermined angle or less. That is, the document detectingdevice 10 detects the starting of closing of the cover 15.

In Act A3 through a route Y of Act A2, the document detecting device 10acquires an image on the glass surface 14. An image at that point intime is acquired.

In Act A4, the document detecting device 10 compares the image of theglass surface 14 without a document, which is stored in advance, withthe image acquired by the scanner 17 in a state where the document isplaced.

FIG. 6 is a diagram illustrating an example of the image acquired by thescanner 17. Reference signs described above represent the samecomponents. FIG. 6 illustrates an example of a state where a document isplaced at an arbitrary position on the glass surface 14.

The document detecting device 10 recognizes that the different portionbetween the images is a portion where a document G is placed.

In Act A5 of FIG. 4, the document detecting device 10 determines whetheror not the image is acquired.

In Act A5, if the different portion exists in FIG. 6, the process of thedocument detecting device 10 proceeds through a route Y, and in Act 6,the document detecting device 10 detects the size, the position, and theinclination amount of the document by the calculation using the image.

FIG. 7 is a flowchart for describing an example of an inclinationcorrecting process by the document detecting device 10.

In Act B1, the document detecting device 10 acquires the positions offour corners of the document as coordinate positions a, b, c, and d. Thecoordinate sets, for example, an upper left point of the glass surface14 as a reference point P.

In Act B2, the document detecting device 10 determines whether or notthe positions of the four corners are detected. If the four positionsare detected, the process proceeds through a route Y of Act B2, and inAct B3, the document detecting device 10 calculates the long side andthe short side of a tetragon abcd.

In Act B3, the document detecting device 10 obtains a horizontal line L1passing through a point a, a vertical line L2 passing through a point b,a horizontal line L3 passing through a point c, and a vertical line L4passing through a point d.

The document detecting device 10 obtains an intersecting point e of thehorizontal line L1 and the vertical line L2, and an intersecting point fof the vertical line L2 and the horizontal line L3.

The document detecting device 10 obtains the length of a side ae byusing a triangle abe. The document detecting device 10 obtains thelength of a side bf by using a triangle bcf.

Sequentially, in Act B4 of FIG. 7, the document detecting device 10calculates an inclination angle of the document.

The document detecting device 10 detects the inclination angle by thecalculating expression in which one or both of the side ae and the sidebf are used.

In Act 7 of FIG. 4, the document detecting device 10 determines whetherthe size, the position, and the inclination amount of the document aredetected. The document detecting device 10 determines the positive orthe negative based on, for example, a return value of the process inFIG. 7.

According to the positive result of the process in Act A7, the documentdetecting device 10 hands over the control to the scanner 17. Thedocument detecting device 10 may transmit the detected information tothe scanner 17.

In Act A8, the scanner 17 (FIG. 2) reads the document surface placed onthe glass surface 14 by the movement of a reading unit (the light source18 and the carriages 28 and 29 and the like).

The light source 18 generates light toward the glass surface 14. Themirror 19 guides the reflected light from the document to the mirror 20.The mirror 20 guides the reflected light from the mirror 19 to themirror 21.

A moving direction of the carriages 28 and 29 is a sub-scanningdirection of the document.

The scanner 17 moves the carriages 28 and 29 in a range defined based onthe detected information.

The scanner 17 generates an image in a range defined by, for example, arange A and a range B (FIG. 6) on the glass surface 14.

The mirror 21 guides the reflected light from the mirror 20 to the lens22. The lens 22 collects the reflected light from the mirror 21. Thelens 22 forms an image on the surface of the 4-line CCD 23 by using thelight.

The 4-line CCD 23 performs photoelectric conversion of light, the imageof which is formed for each color. The 4-line CCD 23 stores a charge foreach color at a sampling interval.

The scanning of the document by the carriages 28 and 29 is completed.The 4-line CCD 23 outputs intensity information for each color of R, G,and B and brightness information for each color of R, G, and B of theentire document.

The scanner 17 generates image data of a region corresponding to thedetected size.

In Act A9, the document detecting device 10 rotates the image based on,for example, the inclination angle obtained by the process of FIG. 7.

In Act A9, the document detecting device 10 selects, for example, thepoint c as a rotational center. The document detecting device 10 selectsa direction in which the inclination angle becomes zero as a rotationaldirection. The document detecting device 10 converts all pixels by therotation of an angle α (FIG. 6).

The document detecting device 10 may adjust the vertical position of theimage after rotation.

In Act A10, the copying machine 100 transmits the read data to theprinting unit 104. The printing unit 104 prints the document on a sheet.The copying machine 100 prints out the sheet.

In addition, in Act A5, if the image is not normally acquired, theprocess of the document detecting device 10 proceeds through a route N,and in Act A11, the document detecting device 10 sends a control signalto the display 37. The display 37 displays the failure of imageacquisition.

The different portion between the images is not detected. Then, thedocument detecting device 10 causes the display 37 to display that thereis no document. The fact that the document is not placed on the glasssurface 14 is notified to a user.

The document detecting device 10 may abnormally end the process afterAct A11.

In addition, if the size, the position, and the inclination amount ofthe document are not detected in Act A7, the process proceeds through aroute N, and in Act A11, the document detecting device 10 causes thedisplay 37 to display the failure.

In addition, in Act B2 of FIG. 7, if the document detecting device 10cannot detect the positions of the four corners, the process proceedsthrough a route N of Act B2, and in Act B5, the document detectingdevice 10 determines that the detection has failed.

The process of the document detecting device 10 proceeds through a routeassigned with J, and the document detecting device 10 causes the display37 to display the failure of image acquisition (Act A11 of FIG. 4).

For example, it is detected that the document protrudes from the surfacearea of a detection target on the glass surface 14. For example, it isdetected that a part of the document is bent.

The four corners of the document are acquired as the coordinatepositions a, b, c, and d, and therefore, the position, the inclination,and the size of the document can be recognized.

It is sufficient for the document detecting device 10 to acquire theimage in the range A in the vertical direction, and to acquire the imagein the range B in the horizontal direction. In the surface area of theglass surface 14, it is not necessary to read the image in otherportions different from the range AB.

The document detecting device 10 extracts only the effective documentrange from the read image data.

According to the rotation of the angle α, the document detecting device10 obtains the image data which is the same as image data that is readat a position at which the document is normally set.

According to the document detecting device 10, it is possible to resolveinconvenience of the user to perform positioning of an image surface tobe read.

The scanning for reading is sufficient for being performed in therequired minimum range AB. Since the scanning is minimally performed,the document detecting device 10 does not use excess power. Therefore,the document detecting device 10 can read the image of the documentunder necessary and sufficient conditions.

Even if the position of the document does not match the designatedposition by the reading unit, according to the document detecting device10, the image can be obtained.

Even if the horizontal direction or the vertical direction of thedocument does not match the moving direction of the reading device, thedocument detecting device 10 can obtain the image.

Even if the user erroneously inputs the document size to the operationpanel 101, according to the document detecting device 10, the image atan accurate position can be obtained. A desired image is obtained.

Even if a document having an unfixed size is placed on the glass surface14, according to the document detecting device 10, the image can be readwith an accurate size.

Modification Example

In the description above, the document detecting device 10 acquires theimage at a point in time when the opened cover 15 starts to be closed.

The image reading timing of the detecting process by the documentdetecting device according to the first embodiment can be variouslymodified.

A document detecting device according to a modification example has aconfiguration substantially the same as the configuration of thedocument detecting device 10, unless otherwise stated.

A document detecting method according to the modification example is amethod in which the determination unit 45 determines whether the openingangle by the angle detector 36 is within the angular range.

According to the positive determination result, the controller 13 causesthe display 37 to display a state in which the position, the angle, andthe size can be recognized.

According to the positive determination result, the controller 13 mayallow the operation panel 101 to receive a recognition operation of theposition, the angle, and the size.

FIG. 8 is a flowchart for describing a detecting process of the documentdetecting device 10 according to a modification example.

The document detecting device 10 having such a configuration detects theopening angle of the cover 15 (Act C1).

In Act C2, the document detecting device 10 determines whether the cover15 is within an angular range.

According to the determination result that the cover is within theangular range, the process of the document detecting device 10 proceedsthrough a route Y to Act C3. The document detecting device 10 causes thedisplay 37 to display that the document detecting device 10 is in astate able to accurately recognize the size, position and shape of theimage.

FIG. 9A is a diagram illustrating a display example of the display 37.Reference signs described above represent the same components.

The user is notified that the opening angle of the cover 15 is withinthe determined range. The user places a document at an arbitraryposition on the glass surface 14.

The document detecting device 10 performs processes after Act A3 in FIG.4 through a route assigned with K in FIG. 8.

In Act C2 in FIG. 8, the document detecting device 10 determines thatthe opening angle is not within the angular range. For example, theopening angle is small.

The process of the document detecting device 10 proceeds through a routeN to Act C4. The document detecting device 10 causes the display 37 todisplay that the document detecting device 10 is in a state not able toaccurately recognize the size, position and shape of the image.

FIG. 9B is a diagram illustrating another display example of the display37. The user adjusts the opening angle of the cover 15 according to thedisplay by the display 37.

The process of the document detecting device 10 returns to Act C1 fromAct C4. If it is detected that the cover 15 is within the angular range,the document detecting device 10 performs the process of Act C3.

In this manner, the document detecting device 10 can accurately obtainan image regardless of the specification of the camera 12 or theattachment position of the camera 12 to the cover 15.

According to the document detecting device of the modification example,there is no limitation on the photographing visual field range. It ispossible to generally secure the opening angle of the cover 15.

In addition, if the opening angle is too wide, the document detectingdevice 10 can guide the user to adjust the opening angle to have morewide angle.

It is possible to prevent the reading failure due to failure of theopening angle.

The document detecting device 10 and the scanner 17 can have a structurein which the opening angle of the cover 15 exceeds 90 degrees withrespect to the glass surface 14.

Even if the opening angle is an obtuse angle with respect to the glasssurface 14, the user can be guided to make the photographing directionof the camera 12 to be in the photographing visual field range.

Second Embodiment

FIG. 10A is a top view of the scanner 17 including a document detectingdevice according to a second embodiment. FIG. 10A illustrates an examplein which the cover 15 is removed.

FIG. 10B is a diagram illustrating a vertical cross-sectional structureof the scanner 17. FIG. 10B illustrates an example taken along line GHof FIG. 10A. In FIGS. 10A and 10B, reference signs described aboverepresent the same components.

A document detecting device 60 includes a camera 46 on the inner bottomportion of the scanner 17.

The photographing direction of the camera 46 is a direction facing therear surface of the glass plate 11.

The photographing visual field range by the camera 46 covers the entireregion of the glass surface 14.

Other than those described above, the document detecting device 60 hasconfiguration constituents substantially the same as those of thedocument detecting device 10.

The document detecting device 60 having such a configuration acquires animage by the detection of the starting of closing of the cover 15.

The document detecting device 60 executes a process substantially thesame as the operation example of FIG. 4.

The document detecting device 60 detects the opening angle of the cover15 (Act A1).

The document detecting device 60 determines whether the opening angle iswithin the angular range (route N of Act A2).

The document detecting device 60 detects the starting of closing of thecover 15 by the opening and closing detector 35 and the angle detector36 (route Y of Act A2).

Next, the document detecting device 60 acquires an image (Act A3).

The document detecting device 60 compares the image of the glass surface14 without a document with the acquired image (Act A4).

The document detecting device 60 determines whether the acquisition ofthe image succeeds (Act A5).

According to the positive determination result, the document detectingdevice 60 detects the size, the position, and the inclination amount ofthe document (Act A6, and Act B1 to Act B4 of FIG. 7).

The document detecting device 60 determines the detection of the size,the position, and the inclination amount of the document succeeds (ActA7).

The scanner 17 scans the document surface (Act A8).

The document detecting device 60 rotates the obtained image (Act A9).

The printing unit 104 prints out the sheet (Act A10).

The document detecting device 60 performs notification of theacquisition failure of the image of the document (Act A11). In a casewhere information on the position, the size and the inclination amountof the document is not obtained, the document detecting device 60performs notification of the failure (Act A11).

The document detecting device 60 may cause the display 37 to display asign indicating the starting of the document acquisition.

In the embodiments described above, the flowcharts of FIGS. 4, 7, and 8are examples, and the document detecting device 10 is not limited to theexamples of the flowcharts. The method of the detecting process can bevariously modified.

In the embodiments described above, the document is pressed onto thesurface by the rear surface of the cover. The rear surface is notnecessary to be normally a plane. For example, the cover may havestrip-shaped parallel pieces that are fixed on the rear side of thecover. A plurality of pieces press the document.

In the embodiments described above, the reading unit (the light source18 and the carriages 28 and 29) is moved in a state where one corner ofthe document matches the reference point P. However, in the documentdetecting device 10, the document on the glass surface 14 may match thecenter of a direction in which the reading unit moves.

Even in an implementation product which is merely implemented byvariously modifying the invention, superiority of the document detectingdevice and the document detecting method is not impaired in any ways.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms; furthermore variousomissions and substitutions and changes in the form of methods andsystems described herein may be made without departing from the spiritof the inventions. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirits of the inventions.

What is claimed is:
 1. A document detecting device comprising: a platehaving an upper surface on which a document is placed, the upper surfacehaving a planar size; a cover that has a rear surface toward the uppersurface, the rear surface having a size that is larger than the planarsize; an automatic document feeder provided over the plate, theautomatic document feeder having a bottom surface larger than the planarsize; an imaging device that is provided at any of the rear surface ofthe cover and the bottom surface of the automatic document feeder andincludes the upper surface in a photographing visual field range; and acontroller that determines whether an opening angle which is formedbetween the upper surface and the bottom surface is within an angularrange in which the imaging device recognizes an entirety of the uppersurface according to angular range information stored in a memory inadvance, the controller detecting one or more of a position, an angle,and a size of the document on the upper surface according to an image bythe imaging device and fixed-size information of the document stored inthe memory in advance.
 2. The device of claim 1, further comprising: ahinge between the plate and the cover, wherein the imaging device isprovided on the rear surface of the cover.
 3. The device of claim 1,further comprising: an opening and closing detector that detects an openstate or a closed state of the automatic document feeder, wherein thecontroller starts calculation of the position, the angle, and the sizeaccording to the detection of the open state by the opening and closingdetector.
 4. The device of claim 1, further comprising: a display,wherein the controller causes the display to display a state in whichthe position, the angle, or the size is recognized according to apositive determination result.
 5. The device of claim 1, furthercomprising: an operation panel, wherein the controller allows theoperation panel to receive a recognition operation of the position, theangle, or the size according to a positive determination result.
 6. Thedevice of claim 1, further comprising: a display, wherein the controllercauses the display to display completion of detecting the position, theangle, and the size according to a positive determination result.
 7. Adocument detecting method comprising: photographing an image includingan upper surface of a plate, the upper surface having a planar size, onthe plate (i) a document being placed, (ii) a cover having a rearsurface toward the upper surface, the rear surface having a size that islarger than the planar size and (iii) an automatic document feeder beingprovided over the plate and having a bottom surface larger than theplanar size, in a photographing visual field range by an imaging deviceprovided at any of the rear surface of the cover and the bottom surfaceof the automatic document feeder, in a state in which a part between theupper surface and the bottom surface of the automatic document feeder isopened; determining by a controller whether an opening angle, which isformed between the upper surface and the bottom surface and detected byan angle detector, is within an angular range in which the imagingdevice recognizes an entirety of the upper surface according to angularrange information stored in a memory in advance; and detecting any oneor more of a position, an angle, and a size of the document on the uppersurface according to the image and fixed-size information of thedocument stored in the memory in advance.
 8. The method of claim 7,wherein in the photographing of the image, the image is photographedafter an opening and closing detector detects that the automaticdocument feeder in an open state starts to be closed.
 9. The method ofclaim 7, wherein in the determining whether the opening angle is withinthe angular range, a display is caused to display a state in which theposition, the angle, or the size is recognized according to a positivedetermination result.
 10. The method of claim 7, wherein in thedetermining whether the opening angle is within the angular range, anoperation panel receives a recognition operation of the position, theangle, or the size according to a positive determination result.
 11. Animage reading device comprising: a plate having an upper surface onwhich a document is placed, the upper surface having a planar size; acover that has a rear surface toward the upper surface, the rear surfacehaving a size that is larger than the planar size; an automatic documentfeeder provided over the plate, the automatic document feeder having abottom surface larger than the planar size; an imaging device that isprovided at any of the rear surface of the cover and the bottom surfaceof the automatic document feeder and includes the upper surface in aphotographing visual field range; and a controller that determineswhether an opening angle which is formed between the upper surface andthe bottom surface is within an angular range in which the imagingdevice recognizes an entirety of the upper surface according to angularrange information stored in a memory in advance, the controllerdetecting any one or more of a position, an angle, and a size of thedocument on the upper surface according to an image by the imagingdevice and fixed-size information of the document stored in the memoryin advance; and a reader that reads the document by a determinationresult indicative that the opening angle is within the angular rangefrom the controller.